Acoustic detection of hidden objects and material discontinuities

Abstract

Sonic excitation is used to locate, without contact, an object or defect beneath a surface. Defects may include, for example, damage and flaws in load bearing concrete structures wrapped in plastic, fiberglass or composite sheathing, while buried objects amenable to detection include landmines or above-ground mines.

Description

RELATED APPLICATION[0001]This application claims the benefits of and priority to U.S. Provisional Application Ser. No. 60 / 670,004 (filed on Apr. 11, 2005), the entire disclosure of which is hereby incorporated by reference.GOVERNMENT SUPPORT[0002]This invention was made with government support under Grant Number F19628-00-C-0002, awarded by the U.S. Air Force. The government has certain rights in the invention.BACKGROUND[0003]Acoustic energy is used in numerous applications to characterize discontinuities within various types of material. Acoustically based techniques rely on differences in mechanical properties between a feature of interest and its surroundings. These differences result in different vibrational responses to sonic excitation, which may be detected and the feature thereby localized and / or characterized.[0004]An important advantage of acoustic techniques is the ability to detect discontinuities corresponding to (or indicating the presence of) flaws or hidden items tha...

AI Technical Summary

Benefits of technology

The PAA system enables safe and efficient detection of landmines and flaws in structures from a distance, reducing operator exposure to harmful sound levels and allowing for faster evaluation of larger areas compared to invasive contact methods, while maintaining sufficient acoustic power to detect buried objects and structural anomalies.

Problems solved by technology

Exceeding a standoff range of 7 meters is a difficult challenge.

While an array of speakers could achieve the acoustic power requirements, the massive size and weight of the array would be impractical for many forms of operational use.

Moreover, the sound level close to an array of speakers would be well above the hearing threshold of pain, thus reducing safety and comfort for the operator and others nearby.

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